Hey there ! i am a veteran lee sin player who plays in the platinum league, Current runes and masteries i use are :
21-9-0
Red: flat ad
Yellow: flat Armor
Blue: mr per level
Quints: flat ad
As the other guys previously said it is wise to get your buffs first and then go for ganks, don't stick around in the jungle early since it isn't lee sin's strenght. Just rush the buffs and get to level 3, after that try to gank lanes and otherwise recall and get your madreds, after you got the madreds jungling is a heck of a lot easyer. Also you can invade the enemy jungler if you were quick with getting your buffs ( Mind your counters tho, e.g. if it's a champion like nocturne who beats you 1v1 you shouldn't invade but if it's like ammumu you should invade.) Anyways i hope i've been helpfull ! Goodluck with the godlike blind monk